Nicad Batteries Tech

8/13/2019 Nicad Batteries Tech

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Table of ContentsTable of ContentsTable of ContentsTable of Contents

Overview of CADNICA BatteriesOverview of CADNICA BatteriesOverview of CADNICA BatteriesOverview of CADNICA Batteries1-1. Advantages and Characteristics of CADNICA (Nickel-Cadmium) Batteries

1-2. Theory of Operation, Manufacturing Processes and Structural Designs of CADNICA Batteries

Charge CharacteristicsCharge CharacteristicsCharge CharacteristicsCharge Characteristics2-1. Outline of Charge Characteristics 2-2. Charge Efficiency 2-3. Cell Temperature during Charge2-4. Internal Gas Pressure during Charge 2-5. Cell Voltage during Charge

Discharge CharacteristicsDischarge CharacteristicsDischarge CharacteristicsDischarge Characteristics3-1. Outline of Discharge Characteristics 3-2. Internal Resistance 3-3. Discharge Capacity

3-4. Polarity Reversal

Storage CharacteristicsStorage CharacteristicsStorage CharacteristicsStorage Characteristics4-1. General 4-2. Storage Conditions 4-3. Items to be Remembered for Storage

Battery Service LifeBattery Service LifeBattery Service LifeBattery Service Life5-1. General 5-2. Factors Influencing Service Life 5-3. Summary of Service Life

Special Purpose BatteriesSpecial Purpose BatteriesSpecial Purpose BatteriesSpecial Purpose Batteries6-1. High-capacity CADNICA Batteries 6-2. Fast-charge CADNICA Batteries

6-3. High-temperature CADNICA Batteries 6-4. Heat-resistant CADNICA Batteries

6-5. Memory-backup CADNICA Batteries

CADNICA SLIMCADNICA SLIMCADNICA SLIMCADNICA SLIM7-1. Characteristics of CADNICA SLIM 7-2. Structure of CADNICA SLIM 7-3. Charge Characteristics

7-4. Discharge Characteristics 7-5. Temperature Characteristics 7-6. Storage Characteristics

7-7. Battery Service Life

Charging Methods and Charging CircuitsCharging Methods and Charging CircuitsCharging Methods and Charging CircuitsCharging Methods and Charging Circuits8-1. Outline of Charging Methods 8-2. Charging Methods 8-3. Quick Charge

8-4. Designing Charging Circuits 8-5. Parallel Charge and Parallel Discharge

Assembled BatteryAssembled BatteryAssembled BatteryAssembled Battery9-1. Outline of Assembled Battery 9-2. How to Assemble Batteries 9-3. Interchangeability with Dry Cells

General Remarks and PrecautionsGeneral Remarks and PrecautionsGeneral Remarks and PrecautionsGeneral Remarks and Precautions


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1Overview ofOverview ofOverview ofOverview of

CADNICACADNICACADNICACADNICA

BatteriesBatteriesBatteriesBatteries1-1 Characteristics of

CADNICA

(Nickel-Cadmium)

Batteries

1-2 Theory of Operation,

Manufacturing Processes

and Structural Designs ofCADNICA Batteries

1-11-11-11-1 Advantages andAdvantages andAdvantages andAdvantages and

Characteristics of CADNICACharacteristics of CADNICACharacteristics of CADNICACharacteristics of CADNICA

(Nickel-Ca(Nickel-Ca(Nickel-Ca(Nickel-Cadmium) Batteriesdmium) Batteriesdmium) Batteriesdmium) Batteries

As an energy storage and conversion system,

CADNICA batteries excel in ease of operation and

electric characteristics, even though being classified

as a secondary battery. Anticipating diversified

market requirements, Sanyo Electric Co., L td. has

put CADNICA batteries to use in sophisticated appli-

cations that call for such requirements as high-speed

charging and high-temperature operation, while

maintaining all the features of general-use

CADNICA batteries. Significant features of the

CADNICA battery are as follows.

(1) Outstanding economy and long service life which

can last over 500 charge/discharge cycles.

(2) Low internal resistance which enables high-rate

discharge, and constant discharge voltage which

guarantees excellent sources of DC power for any

battery-operated appliance.

(3) Sealed construction which prevents leakage of

electrolyte and is maintenance free. No restric-

tion on mounting direction so as to be incorpo-

rated in any appliance.

(4) Abil ity to withstand overcharge and overdischar-

ge.

(5) Long storage life without deterioration in perfor-

mance; and recovery of normal performance on

being recharged.

(6) Operational within a wide temperature range.

(7) Casing made from metal provides extra strength.

(8) Similarities in discharge voltage betweenCADNICA and dry cells allow interchange

ability.

(9) High reliabil ity in performance due to high stan-

dard quality control in manufacturing process

based on ISO9000 standards.


3/52- 2 -

1-1-1-1-2222 Theory of Operation,Theory of Operation,Theory of Operation,Theory of Operation,

Manufacturing ProcessesManufacturing ProcessesManufacturing ProcessesManufacturing Processes andandandand

Structural Designs ofStructural Designs ofStructural Designs ofStructural Designs of

CADNICA BatteriesCADNICA BatteriesCADNICA BatteriesCADNICA Batteries

1-1-1-1- 2222-1-1-1-1 Theory of OperationTheory of OperationTheory of OperationTheory of OperationAs its name suggests, the Nickel-Cadmium battery

has a positive electrode made of nickel hydroxide and

a negative electrode in which a cadmium compound is

used as active material. Potassium hydroxide is used

as its electrolyte. During change and discharge, the

following reactions take place:

(At the positive)

Discharge

NiOOHH2O + e Ni(OH)2+ OH

Charge 0.52(1)

(At the negative)

Discharge

Cd + 2OH

d(

)2 + 2e

Charge 0.80(2)

(Overall)

Discharge

2NiOOH + Cd + 2H2O 2Ni(OH)2+ Cd(OH)2

Charge

1.32(3)

(Standard electromotive force)

Namely, at the positive electrode, changes take place

between nickel oxyhydroxide and nickel hydroxide,

and at the negative electrode between cadmium

metal and cadmium hydroxide.

In Eq. (3) above, potassium hydroxide does not playa role in the electrochemical reaction of the Nickel-

Cadmium battery apparently. In addition, it is a

well-known fact that the H 2O molecules which are

generated during charge disappear during discharge.

Therefore, variations in electrolyte concentration are

insignificant. Because of this reaction, the Nickel-

Cadmium battery excels in temperature character-

istics, high-rate discharge characteristics, durabil ity,

etc. Most significant is the fact that the amount of

electrolyte in a cell can be sizably reduced in order to

allow completely sealed cells to be manufactured.

With any other types of batteries, the discharged

active materials will be exhausted as the batteries

reach a fully charged state. Consequently, electrolysis

of water contained in electrolyte commences. I t is

well-known that at this stage oxygen and hydrogen

gases begin to be generated respectively at the

positive and negative electrodes. This will result in a

decrease of water contained in electrolyte. At the

same time, the gases will build up the internal

pressure of a battery. Finally, the battery will be

destroyed or electrolyte will run short, deteriorating

the charge/discharge characteristics.

Because of its unique design, the CADN ICA battery

is capable of completely consuming the gases that

evolve internally, extending its normal service life.

Some of its notable design features are as follows:

(1) Active materials have greater capacity at the

negative than at the positive electrode.

(2) The electrode used features superior conductivity

and exemplary uniform distribution of its active

materials.

(3) The electrodes are thin plates having a large

surface area. The negative and positive

electrodes sandwich a separator through whichgases freely move. These are wound tightly and

housed in the casing.

(4) The electrolyte in a cell is kept to the precise

quantity needed for the required output capacity.

Fig.1-1 illustrates the charging process of the

CADNICA battery. As shown in this process chart,

the positive electrode becomes fully charged well

before the negative electrode which is larger in

capacity. Then, oxygen gas is generated by the

electrolysis of water in the following manner.

4OH 2H2O + O24e

(4)

Oxygen gas migrates to the negative electrode

where it is recombined and removed from the gas

phase.

Thus, the negative electrode will not become fully

charged and there will be no generation of hydrogen

gas. Because cadmium reacts quickly to oxygen, they

produce cadmium hydroxide at the negative electrode

where cadmium metal is produced on charge. This

takes the process described in Eq. (5).

Gas Recombination

Cd + 1/2O2+ H2O Cd(OH)2

(5) ChargeCd(OH)2+ 2e

Cd +2OH

(2)

The cadmium hydroxide produced by the process

described in Eq. (5) is originally a discharge product

of the negative electrode as is clear from Eq. (2). I f

overcharge current is limited, the reaction rate in Eq.

(5) will ultimately catch up with the reaction rate in

Eq. (4) and a balance wil l be achieved. In other

words, the apparent charging of the negative

electrode will cease to continue any further. This

means that the negative electrode will remain short

of being fully charged all the time and the generationof hydrogen gas will not occur.

Besides the chemical recombination mechanism of

oxygen gas described above, oxygen gas is recom-

bined electrochemically in the CADNICA battery.

As explained previously, the CADNICA battery is

composed of electrodes which have very large surface

areas. These are placed side by side, sandwiching a

separator which allows the free passage of gaseous

substance. Accordingly, the oxygen gas generated at

the positive electrode moves through the separator

and reaches into the negative electrode, where it is

quickly reduced due to the prevalent state of


4/52- 3 -

potential. Consequently, at the boundaries of three

phases namely oxygen gas (gas), electrolyte

(liquid) and negative electrode (solids) the reac-

tion shown in Eq. (6) takes place, causing oxygen gas

to be recombined.

2H2O + O2+ 4e 4OH

(6)

The CADNICA battery has a mechanism of

completely disposing of the entire quantity of oxygengas generated in its sealed casing.

Fig.1-1:Fig.1-1:Fig.1-1:Fig.1-1: Gas-Recombining MechanismGas-Recombining MechanismGas-Recombining MechanismGas-Recombining Mechanism

of CADNICA Batteryof CADNICA Batteryof CADNICA Batteryof CADNICA Battery

o2o2

o2

o2 o2 o2

Positive

Negative Negative Negative

S epa rator

Positive Positive

Before fully charged(Charging reactionproceeds almostquantitatively.)

After full charge,gas is generated.(Positive electrodeis fully charged.)

Being overcharged,gas is consumed atnegative electrode.

Charged section Uncharged section

Electrode

1-1-1-1- 2222-2-2-2-2 Manufacturing Processes ofManufacturing Processes ofManufacturing Processes ofManufacturing Processes of

CADNICA BatteriesCADNICA BatteriesCADNICA BatteriesCADNICA Batteries In order to guarantee the performance character-

istics which a sealed sintered Nickel-Cadmium cell

should possess, its manufacturing processes are very

sophisticated and consist of many stages, A sintered

plate, for example, is processed as follows to

guarantee the critical quality needed to maintain the

excellent performance of CADNICA batteries.

First of all, nickel powder, which is very small in

apparent specific gravity and large in specific surface

area, is mixed with a thickening agent and water

which in turn is applied on both faces of a core

substance, such as thin nickel-plated steel plate,

dried, and then sintered in reducing atmosphere so

as to produce a sintered base plate of 80 to 85

porosity, and 0.4 to 0.8mm thickness. The quality of

this plate, which supports active materials, has great

bearing upon the performance characteristics of

sealed cell to be manufactured.

In the next stage, active materials, which are

produced from nickel and cadmium salts and which

are insoluble in water, are loaded in the plate. This

process is most important because the characteristics

of the plate are determined in this stage. At Sanyo,

this process is controlled with great care and

constant improvements have been made for better

results.

The active materials are then reactivated and

washed clean before the electrodes are wound in a

roll, being isolated from each other by a porous

separator. I n the final process, they are assembled

into a cell and are made ready to undergo strict

inspections prior to shipment form the factory.


5/52- 4 -

1-1-1-1- 2222-3-3-3-3 Structural Designs of CADNICAStructural Designs of CADNICAStructural Designs of CADNICAStructural Designs of CADNICA Sanyo CADNICA batteries range in type from

standard batteries to fast-charge batteries, or high

temperature batteries for exclusive use as well as in

capacity from 45mAh to 20 Ah to meet diverse user

requirements. Though each type has its own

structural design according to its required

performance, the basic structural design is identical.

Fig.1-2 illustrates the internal view of a CADNICA

battery where the electrodes are very thin sinteredplates wound compactly in a roll and insulated from

each other by a porous separator. Almost the entire

room inside the cell casing is occupied by this roll so

that energy efficiency as well as charge/discharge,

and temperature characteristics are raised to the

highest possible levels. The cell casing is made of

solid steel.

Although Sanyo CADNICA batteries are designed to

completely recombine gas generated within their

casings, they have a gas release vent, as illustrated

in Fig.1-3, which opens automatically and releases

excessive pressure when the internal gas pressure

increases. Then it is resealed so that the battery can

be used again. F urthermore, because Sanyos origi-

nal current collector is employed for both the positive

and negative tabs(some models excepted), internal

impedance is extremely small and excellent

characteristics are exhibited, even under high-rate

discharge conditions.

Fig.1-2:Fig.1-2:Fig.1-2:Fig.1-2: Structural DesignStructural DesignStructural DesignStructural Design of CADNICAof CADNICAof CADNICAof CADNICA

BatteryBatteryBatteryBatteryElectricWelding

Positive tab

Negativeelectrode

Separator

Positive electrode

Spring

Seal plate

Rubber plate

Positive current collector

Separator

Positiveelectrode

Negativeelectrode

Enlargement

Positive cap

Cover plate

Gasket

Casing

Negativetab

Fig.1-3:Fig.1-3:Fig.1-3:Fig.1-3: Structural Design of GasStructural Design of GasStructural Design of GasStructural Design of Gas

Release VentRelease VentRelease VentRelease VentPositive cap

Seal plate

Rubber plate

Spring

Gasket

Over plate

Casing


6/52- 5 -

2ChargeChargeChargeCharge

CharacteristicsCharacteristicsCharacteristicsCharacteristics2-1 Outline of Charge

Characteristics

2-2 Charge Efficiency

2-3 Cell Temperature

during Charge

2-4 Internal Gas Pressure

during Charge

2-5 Cell Voltage

2-12-12-12-1 Outline of ChargeOutline of ChargeOutline of ChargeOutline of Charge

CharacteristicsCharacteristicsCharacteristicsCharacteristics

CADNICA batteries should be charged with

constant or quasi-constant current. As illustrated in

Fig.2-1, the general characteristics of CADNICA

batteries such as cell voltage, internal gas pressure

and cell temperature vary during charge, depending

on charge current and ambient temperature.

Fig.2-1:Fig.2-1:Fig.2-1:Fig.2-1: Charge CharacteristicsCharge CharacteristicsCharge CharacteristicsCharge Characteristics

1.0

1.1

1.2

1.3

1.4

1.5

10 12 14 16 18 200

0.1

0.2

0.3

0.4

0.5

0.6

86420

10

0

20

30

40

50

C e ll voltag e

C ell tem pe rature

Internal ga s pressure

N -1300S C

C h arge0.1ItTe m perature20

As mentioned in Section 1-4 above, the sealed

structure of CADNICA batteries has been achieved

by recombining oxygen gas, which is generated at the

positive electrode during overcharging, at the

negative electrode. However, since recombining

capacity is limited, the charge current of each model

is determined by first calculating the balance of

oxygen gas generated at the positive electrode

against the negative electrodes gas recombination

capability.

As long as the input rate is kept lower than thespecified value, internal gas pressure during

charging will stay low and oxygen generation will not

be excessive even in the late period of charging.

The fast-charge type of Sanyo CADNICA batteries is

designed to accelerate oxygen gas recombination,

permitting a charge rate of 0.3It for some models.

1 hour charge is also possible with a simple external

circuit.

2-22-22-22-2 Charge EfficiencyCharge EfficiencyCharge EfficiencyCharge Efficiency

Charge efficiency is the term expressing howeffectively input energy is used for charging the

active materials into a useful, dischargeable form as

against total input energy and can be defined as

follows:

Charge Efficiency()

={ }100 Input energy is used to convert the active materialsinto a charged form, and the side reactions togenerate oxygen gas, etc. Fig.2-2 shows thecorrelations of input energy to the output capacity,

Discharge CurrentDischarge

Time to D ischar ge E nd Vol tageCharge CurrentCharge Time100


7/52- 6 -

and the charge input to charge efficiency when acompletely discharged cell is charged at the rate of0.1It. The figures given for charge input anddischarge capacity are shown as a percentage ofnominal battery capacity. Charge efficiency variesconsiderably in the course of charging as seen in the

figure. The dotted line indicates an ideal cell of 100

charge efficiency.

In area, of the charts below, electric energy is

mainly consumed for the conversion of activematerials in the electrode into a chargeable form.

Therefore, charge efficiency is low at this stage. I n area, which marks the middle of the charging

process, charging is carried out in a near ideal state,with almost all of the input energy used for theconversion of active materials.

In area , the cell approaches the state of full

charge. There the input energy is used for thereaction which generates oxygen gas. The chargeinput is lost and consequently charge efficiencydecreases.

Fig.2-2:Fig.2-2:Fig.2-2:Fig.2-2: Charge EfficiencyCharge EfficiencyCharge EfficiencyCharge Efficiency

20

0

40

60

80

100

120

140

200180160140120100806040200

N -1300 S C

C harge0.1ItD ischarge0.2It,E .V .=1 .0VTe m perature20

20

0

40

60

80

100

200180160140120100806040200

23

1

100%

E fficien cyLine

Charge efficiency depends on charge rate. Fig.2-3 is

a chart on the correlations existing between the

charge input and the output capacity, as functions of

charge rate. The chart shows that the charge

efficiency as well as the output capacity is lower at a

lower charge rate.

Be sure to charge within the current range specified.When charging is performed out of the specified

current range, charging efficiency is reduced and the

battery cannot be fully charged.

Fig.2-3:Fig.2-3:Fig.2-3:Fig.2-3: Charge EfficiencyCharge EfficiencyCharge EfficiencyCharge Efficiency vsvsvsvs

Charge RateCharge RateCharge RateCharge Rate

0.01It

0.02It

0.033It0.1It1It

N -1300SC

20

0

40

60

80

100

120

140

200180160140120100806040200

Tem p20

Charge efficiency also depends on ambient

temperature during charge. F ig.2-4 illustrates the

correlations between charge input and discharge

capacity, using the ambient temperature as a

parameter. It is noted that there is a slight decrease

in cell capacity in the high temperature range due to

a fall in potential for oxygen gas generation at the

positive electrode. This decrease in cell capacity is a

temporary phenomenon and the cell capacity will berecovered when charged at normal temperature.

Fig.2-5 illustrates the cell capacity vs ambient

temperature.

Fig.2-4:Fig.2-4:Fig.2-4:Fig.2-4: Charge EfficiencyCharge EfficiencyCharge EfficiencyCharge Efficiency vs Ambientvs Ambientvs Ambientvs Ambient

TemperaTemperaTemperaTemperaturetureturetureN -1300S C

200

40

20

0

40

60

80

100

120

140

200180160140120100806040200

C h arge0.1It


8/52- 7 -

Fig.2-5:Fig.2-5:Fig.2-5:Fig.2-5: Discharge CapacityDischarge CapacityDischarge CapacityDischarge Capacity vs Ambientvs Ambientvs Ambientvs Ambient

TemperatureTemperatureTemperatureTemperature

20

0

40

60

80

100

3020100 40 50 60

N -1300 S C

C harge0.1It,0.033It16 0

D ischarge0.2It,E .V .=1 .0VTe m p erature during discharge20

0.1It

0.033ItR ate

The charge efficiency depends largely on charge rate

and ambient temperature; therefore the appropriate

type of CADNICA battery should be selected

according to the operating requirements.

2-32-32-32-3 Cell TemperatureCell TemperatureCell TemperatureCell Temperature

during Chargeduring Chargeduring Chargeduring Charge Though charging reaction in CADNICA batteries is

in itself endothermic, cell temperature changes very

little during the initial and intermediate steps of

charging and is compensated by heat generated by

internal resistance. Input energy during overcharge

is converted to heat energy which is generated

through gas recombination reaction; therefore the

cell temperature rises. The following factors may

cause cell temperature to rise:

(1) Charge current

(2) Cell design

(3) Design of battery, (shape, number of cells, etc.)(4) Ambient condition, (temperature, ventilation,

etc.)

F ig.2-6 il lustrates the correlation cell temperature

rise vs charge current with respect to different types

of batteries. Here generated heat increases with

charge current, and so does the value of temperature

rise which also depends on battery type in proportion

to its size. The battery arrangement or the thermal

conductance of casing materials becomes important

for battery assemblies where the closely packed

arrangement, or the poor thermal conductance of

casing materials, causes a larger temperature rise.

Any battery should be charged at a normal ambient

temperature, and the charging conditions should be

carefully selected after due consideration to the heat

generation of cells. The fast-charge batteries are

controlled according to generated heat during over-

charge, so the investigation of heat generation

becomes more significant. Details on this subject may

be found in paragraph 6-2.

Fig.2-6:Fig.2-6:Fig.2-6:Fig.2-6: ChargeChargeChargeCharge Current and CellCurrent and CellCurrent and CellCurrent and Cell

Temperature RiseTemperature RiseTemperature RiseTemperature Rise

Note: Measured With Single Cell

2

6

8

10

12

14

16

18

20

0.2 0.3 0.4 0.50.100

4

C harge Input200Tem p20

KR -7000F

N -1300SC

N -600AA

KR -4400D

2-42-42-42-4 Internal Gas PressureInternal Gas PressureInternal Gas PressureInternal Gas Pressure

during Chargeduring Chargeduring Chargeduring Charge

In CADNICA batteries, oxygen gas generated

during overcharge is recombined in the sealed cell.

When continuing charging with the specified cur-rent,

the internal gas pressure achieves a balance

according to the gas generation and recombination

rate.

Fig.2-7 shows changes in internal gas pressure

when a newly produced cell is tested by varying the

charge input after the onset of overcharge. Oxygen

gas is generated in an amount proportionate to the

charge current on overcharge and causes the internal

gas pressure to build up.

Fig.2-7:Fig.2-7:Fig.2-7:Fig.2-7: Overcharge Current and InternalOvercharge Current and InternalOvercharge Current and InternalOvercharge Current and Internal

Gas Pressure at EquilibriumGas Pressure at EquilibriumGas Pressure at EquilibriumGas Pressure at Equilibrium

0.2

0.6

0.8

1.0

0.2 0.3 0.4 0.50.1

0.4

Te m p20

N -1300S C

00

The internal gas pressure tends to increase with

lower ambient temperature as shown in F ig.2-8. Thegas recombination rate at the negative electrode

decreases with lower ambient temperature so that

the charge current should be accordingly lower.

Fig.2-9 shows a sample of recommended charging

current at low temperatures.


9/52- 8 -

Fig.2-8:Fig.2-8:Fig.2-8:Fig.2-8: CharCharCharCharge Temperature andge Temperature andge Temperature andge Temperature and

Internal Gas PressureInternal Gas PressureInternal Gas PressureInternal Gas Pressure

N -1300S C

N -1300 S C R

C h arge0.3It

0.2

0

0.6

1.0

20 30 40100

0.4

0.8

KR -1300S C

C h arge0.1It

0.6

1.0

20 30 40100

0.4

0.8

0.2

0

Fig.2-9:Fig.2-9:Fig.2-9:Fig.2-9: Ambient Temperature andAmbient Temperature andAmbient Temperature andAmbient Temperature and

Recommended Charge CurrentRecommended Charge CurrentRecommended Charge CurrentRecommended Charge Current

Note: For some models, charge currents differ from the

figures shown above.

0-10-200

0.02

0.1

0.2

10 20 30

2-52-52-52-5 Cell VoltageCell VoltageCell VoltageCell Voltage

The cell voltage of Sanyo CADNICA batteries varies,

depending on charge current, ambient temperature

during charge, cell design and other factors.

The cell voltage increases in the course of charging,

and drops slightly in the end to its equilibrium valuebecause of heat generation within the cell, as shown

in Fig.2-1. F ig.2-10 illustrates the cell voltage as a

function of charge current where charge voltage goes

higher with an increase in charge input, accompanied

by increased internal resistance and polarization

values inside the cell.

The cell voltage also depends on ambient tempera-

ture, as shown in Fig.2-11, where the temperature

rise results in voltage decrease.

As the temperature climbs, there is a decrease in

internal resistance as well as in oxygen gas

generation potential. During charge at the 0.1It rate,

charge voltage fluctuates within a range of 3.0 to

4.0mV/degree. Fig.2-12 illustrates the range of cell

voltage at the end of charging in relation to ambient

temperatures at the charge rate of 0.1It.

Fig.2-10:Fig.2-10:Fig.2-10:Fig.2-10: Charge Current and CellCharge Current and CellCharge Current and CellCharge Current and Cell

VoltageVoltageVoltageVoltage

20 40 60 80 100 120 140 160 180 200

1.4

1.5

1.6

N -1300S C

1.2

1.10

1It0.1It0.033It0.02It

1.3

20 40 60 80 100 120 140 160 180 200

1.4

1.5

1.6

1.7

K R -1300S C

1.2

1.10

0.1It0.033It0.02It

Te m perature20

Tem perature20

1.3


10/52- 9 -

Fig.2-11:Fig.2-11:Fig.2-11:Fig.2-11: Ambient Temperature and CellAmbient Temperature and CellAmbient Temperature and CellAmbient Temperature and Cell

VoltageVoltageVoltageVoltage

20 40 60 80 100 120 140 160 180 200

1.4

1.5

1.6

1.7N -1300SC

1.2

1.10

0

20

45

1.3

charge0.1It

Fig.2-12:Fig.2-12:Fig.2-12:Fig.2-12: Ambient Temperature and CellAmbient Temperature and CellAmbient Temperature and CellAmbient Temperature and Cell

VoltaVoltaVoltaVoltage at the End of Chargingge at the End of Chargingge at the End of Chargingge at the End of Charging

0 10 20 30 40 50 601.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

cha rge0.1It

KR -1300S C

N -1300S C

CellVoltageat

theEndofCharging


11/52- 10 -

3DischargeDischargeDischargeDischarge

CharacteristicsCharacteristicsCharacteristicsCharacteristics3-1 Outline of Discharge

Characteristics

3-2 Internal Resistance

3-3 Discharge Capacity

3-4 Polarity Reversal

3-13-13-13-1 Outline of DischargeOutline of DischargeOutline of DischargeOutline of Discharge


Discharge voltage and cell capacity (self-sustaining

discharge duration) are the units commonly employ-

ed to express the discharge characteristics of

batteries. The voltage of a Nickel-Cadmium cell

remains almost constant at 1.2V until most of its

capacity is discharged. Discharge voltage dropsvery little even during high current discharge, and a

great amount of current more than 100It can be

discharged in a very short time.

The capacity of CADNICA batteries is defined in

terms of the time from the start to the end of

discharge multiplied by the discharge current, where

the unit is Ah, (ampere hours), or mAh, (milliampere

hours).

The capacity given for each type of CADNICA

battery is specified by a 5 hour rate at 0.2It discharge

current. However, the actual capacity depends on

discharge current and ambient temperature.

Fig.3-1 compares the discharge characteristics of anordinary dry cell and a CADNICA battery. The cell

voltage decreases with discharge in an ordinary dry

cell , while the CADNICA battery exhibits an

excellent characteristics of constant discharge

voltage due to its low internal resistance, and less

variation during discharge.

Fig.3-1:Fig.3-1:Fig.3-1:Fig.3-1: Discharge CharacteristicsDischarge CharacteristicsDischarge CharacteristicsDischarge Characteristics

of Ordinary Dry Cell andof Ordinary Dry Cell andof Ordinary Dry Cell andof Ordinary Dry Cell and

CADNICA BatteryCADNICA BatteryCADNICA BatteryCADNICA Battery

0

20

300

400

500

600

700

1.0

1.2

1.4

1.6

10 2 3 4 5 6

D ischarge300m A

Tem p20D ischarge voltage o f C A D N IC A

battery(N -200 0C )

D ischarge voltageof dry cell(R14 )

Internal resistance o f dry ce ll(R14 )

Internal resistance of C A D N IC A b attery (N -2000C )

0.6

0.8

0.4


12/52- 11 -

3-23-23-23-2 Internal ImpedanceInternal ImpedanceInternal ImpedanceInternal Impedance

As mentioned previously, the discharge voltage of a

CADNICA battery remains stable for a long duration.

One of the factors which explain this is the batterys

low internal impedance. The low internal impedance

is due mainly to the use of thin and large surface

sintered nickel plates which exhibit excellent

conductivity. and a thin separator of nonwoven fabric

which exhibits excellent electrolyte retention.

Internal impedance is a key parameter for the

discharge characteristics of batteries.

3-2-13-2-13-2-13-2-1 Components of InternalComponents of InternalComponents of InternalComponents of Internal

ResistanceResistanceResistanceResistance Discharge voltage of CADNICA batteries is expres-

sed as below:

V = E0 IZ

where: E0= no load or open circuit voltage

I =discharge current

Z = internal resistance

This equation confirms that discharge voltage is

higher with lower internal resistance. Internal

resistance consists of 3 resistive components: Z = r +

r + jX. I n this equation, r represents ohmic

resistance due to conductivity or structure of current

collector, electrode plates, separator, electrolytes, etc.

The rdenotes the resistance due to polarization,

when polarization is a phenomenon where the

electrode potentials value deviates from the equilib-

rium one when current circulates through the

electrodes. Ohmic resistance r is independent of

current, while polarization r varies in acomplicated way according to current. r also

value with time and needs several seconds to reach

its equilibrium value. Thus r is negligible for

discharge pulse duration of a few milliseconds. jX

denotes reactance for example, the resistance caused

by alternating-current wave.

The reactance is very low at normal charge/dis-

charge. Thus, discharge voltage during discharge is

written as below:

V = E0I(r+r) (during discharge)

V = E0Ir (momentary, after start of

discharge and for dischargepulses of a few milliseconds.)

The internal impedance of a cell varies due to

various factors. As shown in F ig.3-2, the internal

impedance of CADNICA batteries undergoes almost

no change during discharge from the state of full

charge to the point where 90% of its capacity has

been dissipated. After that point it increases due to

the conversion of active materials in the electrode

plates into hydroxides, which tend to lower electrical

conductivity.

Fig.3-3 il lustrates the effect of ambient tempera-

tures on internal resistance. The internal impedance

increases as the temperature drops, because the

conductivity of electrolytes is lower at lower tempe-

ratures.

Fig.3-2Fig.3-2Fig.3-2Fig.3-2 Internal Impedance andInternal Impedance andInternal Impedance andInternal Impedance and

Discharge CapacityDischarge CapacityDischarge CapacityDischarge Capacity16

14

12

10

8

6

4

2

00 20 40 60 80 100

C harge0.1It16H rsD ischa rge0.2It

Te m p20N -600A A

N -1300S C

Fig.3-3:Fig.3-3:Fig.3-3:Fig.3-3: Internal Impedance andInternal Impedance andInternal Impedance andInternal Impedance and

Cell TempeCell TempeCell TempeCell Temperatureratureraturerature

20

Fully charged cell

N -1300SC

N -600AA

0 20 40 60

16

14

12

10

8

6

4

2

0

3-2-23-2-23-2-23-2-2 Measurements of InternalMeasurements of InternalMeasurements of InternalMeasurements of InternalImpedanceImpedanceImpedanceImpedance There are two methods of measuring internal

impedance; the direct-current method and the

alternating-current method. The internal impedance

of CADNICA batteries is difficult to estimate because

of its low impedance and complicated variables.

(1) Direct-current method

Fig.3-4 illustrates a basic wiring diagram for this

method. Close the switch Sw and record the changes

of current and voltage while adjusting the variable-

resistance Rv. When the change of variable-

resistance is low, then the voltage change is

approximated by a straight line; where it drops off

and gives the value of internal impedance.

That is, R =

The internal impedance estimated by the direct-

current method is equal to r + r, as mentioned

before, where the polarization term is included, so

that it varies with the increase in current, or the

current circulation period.

V

I


13/52- 12 -

Fig.3-4:Fig.3-4:Fig.3-4:Fig.3-4: Internal Impedance MeasuredInternal Impedance MeasuredInternal Impedance MeasuredInternal Impedance Measured

by Direct Current Methodby Direct Current Methodby Direct Current Methodby Direct Current Method

V

A

Battery

SW

I

(2) Alternating-current method

The alternating-current method is used to avoid the

influence of polarization. The basic circuit for the

alternating-current method consists of an AC power

supply circuit and a voltage detection circuit, as

shown in Fig.3-5.

The alternating-current impedance is calculated from

the voltage drop at constant alternating-current

through a cell as:

Z =

The impedance estimated by the alternating-current

method is equal to r + jX, where the reactance term is

included, though polarization is negligible.

Impedance when using AC current varies according

to current frequency. The technical data of Sanyo

gives the value estimated by the alternating-current

method (at 1 KHz) unless otherwise specified.

Fig.3-5:Fig.3-5:Fig.3-5:Fig.3-5: Measuring Internal ResistanMeasuring Internal ResistanMeasuring Internal ResistanMeasuring Internal Resistancececece

by Alternating-Current Methodby Alternating-Current Methodby Alternating-Current Methodby Alternating-Current Method

Battery

AC ppowersupply circuit

Voltagedetection circuit

i

V

3-33-33-33-3 Discharge CapacityDischarge CapacityDischarge CapacityDischarge Capacity

The capacity of CADNICA batteries is derived from

the discharge current and the time from start to

finish of discharge. Here the influence of discharge

end voltage, discharge rate, ambient temperature

during discharge, etc., on discharge capacity will be

discussed.

3-3-13-3-13-3-13-3-1 Discharge End VoltageDischarge End VoltageDischarge End VoltageDischarge End Voltage When estimating battery capacity and discharge in

actual applications, the discharge end voltage is

defined as the limiting voltage when a battery is con-

sidered to have no residual capacity. The standard

end voltage adopted for CADNICA batteries is 1.0

V/cell. The end voltage can be 1.1 V/cell, (for signal of

emergency lamps), or 1.02 V/cell, (for automatic fire

alarms), according to operational requirements.

CADNICA batteries have extremely stable voltage

characteristics during discharge, and the voltage

drop occurs suddenly at the end of discharge, so that

the difference in the discharge capacity is minorwhen specified in terms of the end voltage around 1.0

V/cell. The difference in the discharge time at the 1 It

rate would be within a range of 1 to 2 minutes

between the end voltage, 1.0 V/cell and 1.1 V/cell.

Since the cell voltage drops at high current discharge,

the energy stored in the battery may not be fully

discharged with discharge end voltage higher than

1.0 V/cell.

v

i


14/52- 13 -

3-3-23-3-23-3-23-3-2 Discharge RateDischarge RateDischarge RateDischarge Rate The discharge capacity of a cell decreases as the

discharge current increases, as shown in Fig.3-6,

since the active materials of electrodes are used less

effectively with higher discharge current. Fig.3-7

illustrates that the discharge voltage drops as the

discharge current increases. The reason is an

increased loss of energy due to internal resistance.

Compared with other batteries, CADNICA batteries

have an excellent high current discharge capabilitieswhere the continuous discharge at the rate of 4 I t or,

in some types, a high current discharge of over 10 It

is possible.

Fig.3-6:Fig.3-6:Fig.3-6:Fig.3-6: Discharge Rate andDischarge Rate andDischarge Rate andDischarge Rate and

Discharge CapacityDischarge CapacityDischarge CapacityDischarge Capacity

N -1300S C

0 2 4 6 80

20

40

60

80

100

120

C harge0.1It16H rs.

D ischargeE..1.0

Tem p20

Fig.3-7:Fig.3-7:Fig.3-7:Fig.3-7: Discharge VoltageDischarge VoltageDischarge VoltageDischarge Voltage

CharactCharactCharactCharacteristicseristicseristicseristics

0 20 40 60 80 100 120

0.8

1.0

1.2

1.4

8 It 4 It 1 It 0 .2 It

N -1300SC

C harge0.1It16 H rs.

Tem p20

3-3-33-3-33-3-33-3-3 Ambient TemperatureAmbient TemperatureAmbient TemperatureAmbient Temperature Sanyo CADNICA batteries can be used over a very

wide temperature range, from. 20 to + 60.

Though the discharge characteristics will not change

as the temperature increases, a drop in temperature

causes internal impedance to be higher, and active

materials to be less reactive, so that the discharge

capacity as well as the discharge voltage decreases.

The tendency is more marked in higher rates of

discharge. This decrease of discharge capacity is atemporary phenomenon, much like the decrease in

capacity at high-temperature. Figs.3-8 and 3-9

illustrate the discharge temperature characteristics

and the discharge voltage characteristics of

CADNI CA batteries.

Fig.3-8:Fig.3-8:Fig.3-8:Fig.3-8: Discharge TemperatureDischarge TemperatureDischarge TemperatureDischarge Temperature


20 0 20 40 600

20

40

100

N -1300S C

60

80

C harge0.1It16H rs.,20D ischa rgeE..1.0

0.2It R ate

1It R ate

Fig.3-9:Fig.3-9:Fig.3-9:Fig.3-9: Discharge VoltageDischarge VoltageDischarge VoltageDischarge Voltage


0 20 40 60 80 100 120

0.8

1.0

1.2

1.4

N -1300S C

20 0 20 60

C harge0.1It16H rs.,20

D isch ag e rate0.2It


15/52- 14 -

3-43-43-43-4 Polarity ReversalPolarity ReversalPolarity ReversalPolarity Reversal

Deep discharge of series connected cells, when

differences in residual capacity between cells exist,

may cause one of the cells to reach the state of

complete discharge sooner then the others. As it

becomes over-discharged, its polarity is reversed. See

Fig.3-10 for the discharge voltage curve of the cell on

forced discharge, including polarity reversal.

Section of the graph shows the period when

recharged active materials remain on both positive

and negative electrodes, with charging voltage at

normal levels.

Section shows the period when all the active

materials on the positive electrode have been

discharged and hydrogen gas starts to be generated

on the positive electrode, creating a hydrogen gas

build up inside the cell. Active materials still remain

at the negative electrode, however, and discharging

continues at this electrode. Cell voltage changes

according to discharge current, but stays about 0.2

0.4V.

In section, discharging has been completed at both

the positive and negative electrode, and oxygen gas

starts being generated at the negative electrode. I n

prolonged discharging where this type of polarity

reversal takes place, gas pressure within the cell

rises, resulting in operation of the gas release vent.

This also leads to a breakdown of the balance of the

charging capacity of the positive and negative

electrodes, thus prolonged discharge should be

strictly avoided.

I f a cell is left connected to a load for a long period of

time, the cell will eventually become completely

discharged and its output voltage wil l drop to 0V. Ifthis occurs, the polarity of the positive electrode will

become negative(0.8V) and electrolyte may easily

creep. Therefore, avoid leaving a cell connected to a

load for too long a time.

Fig.3-10:Fig.3-10:Fig.3-10:Fig.3-10: Polarity ReversalPolarity ReversalPolarity ReversalPolarity Reversal

P ositive E lectrode

P ositive E lectrode

N egative E lectrode

2 31

1.0

0

1.0

1.0

0

1.0

DischargeTime

N egative E lectrode

P olarity of po sitiveelectrode reve rsed

P olarity o f bothelectrode reve rsed


16/52- 15 -

4StorageStorageStorageStorage

CharacteristicsCharacteristicsCharacteristicsCharacteristics4-1 General

4-2 Storage Conditions

4-3 Items to be Remembered

for Storage

4-14-14-14-1 GeneralGeneralGeneralGeneral

Generally speaking, a loss of voltage and capacity of

batteries due to self-discharge during storage is un-

avoidable. With open-type Nickel-Cadmium batteries,

or manganese dry cells, this self-discharge is less

notice-able than with CADNICA batteries which

have a large facing electrode area and a limited

amount of electrolyte, all of which are completely

sealed.

The following 2 factors greatly affect the self-

discharge of Nickel-Cadmium batteries while stor-

age:

(1) Instability of active materials.

Nickel oxide is thermodynamically unstable at

its charged state and self-decomposes gradually

to generate oxygen gas, which in turn oxidizes

the negative electrode. Thus, the self-discharge

proceeds.

(2) Impurities in electrodes or electrolyte.

A typical example is the self-discharge due to

nitrate impurities. Nitric ion, NO3, is reduced

from a negative electrode to nitrous ion, NO2

which diffuses to a positive electrode, and is

oxidized. Thus, the self-discharge proceeds.

The portion of the capacity of CADNICA batteries

which is dissipated by self-discharge may, however,

be completely restored when recharged.

4-24-24-24-2 Storage ConditionsStorage ConditionsStorage ConditionsStorage Conditions

4-2-14-2-14-2-14-2-1 Storage TemperatureStorage TemperatureStorage TemperatureStorage TemperatureCADNICA batteries can be stored at temperatures

ranging from 30 to 50 without essential

deterioration in performance. The organic materials,

such as gasket or separator, may deteriorate or

become deformed at high temperatures during

prolonged storage. Thus, it is recommended that

CADNICA batteries be stored at temperature below

35 if there is a possibility of prolonged storage

surpassing 3 months.

A decrease in capacity during storage is determined

mainly by ambient temperature. F ig.4-1 illustrates

self-discharge characteristics of CADNICA batteries

stored at 0, 20, 30 and 45.


17/52- 16 -

Fig.4-1:Fig.4-1:Fig.4-1:Fig.4-1: Storage CharacteristicsStorage CharacteristicsStorage CharacteristicsStorage Characteristics

0

20

40

60

80

100

0 1 2 3

0

20

3045

N series

C harge0.1It16H rs.D isch arge0.2It,E ..1.0Storage tem peratures0,20,30,45

0

20

30

45

KR series

0

20

40

60

80

100

0 1 2 3

Storage TimeMonths

C harge0.1It16H rs.D ischarge0.2It,E ..1.0storagetem peratures0,20,30,45

Fig.4-2 shows the relationship between ambient

temperature and the self-discharge current of

CADNICA batteries, using this graph, the approxi-

mate self-discharge current can be determined as

shown by the example.

Fig.4-2Fig.4-2Fig.4-2Fig.4-2 Self-Discharge Current andSelf-Discharge Current andSelf-Discharge Current andSelf-Discharge Current and

Ambient TemperatureAmbient TemperatureAmbient TemperatureAmbient Temperature

1

2

3

5

710

2018

30

5070

100

200

300

10 0 10 20 30 40 50

E xam ple:The self-discha rge current Is of N -600A A at 20is estimated as: Is=(nominal capacity)(self-discharge current ItmA) =(600)(1810-5)(mA)=10810-3(mA) =108(A)

Fig.4-3 illustrates the capacity recovery characteris-

tics after prolonged storage at respective tempera-

tures. The inactivity of active material is increased

during high-temperature storage, and as a result, the

capacity recovery time may be longer. As mentioned

before, it is recommended that CADNICA batteries

be stored at low temperatures.

Fig.4-3:Fig.4-3:Fig.4-3:Fig.4-3: Storage Temperature andStorage Temperature andStorage Temperature andStorage Temperature and

Capacity RecoveryCapacity RecoveryCapacity RecoveryCapacity Recovery

CharacteristicCharacteristicCharacteristicCharacteristicN -1300SC

50

60

70

80

90

100

10 2 3 4 5

S torage a t 20

Storage a t 35Storage a t 45

R ecove ry after 2yea rsstorage in discharge state

C apa city m easu ring cond itions:C harge:0.1It16H rs.D ischarge:0.2 It, E .V .=1 .0VTe m perature:20

Number of Cycles after Storage

4-2-24-2-24-2-24-2-2 Battery ConditionsBattery ConditionsBattery ConditionsBattery Conditions CADNICA batteries may be stored in charged or

discharged state. Fig.4-4 compares the capacity

recovery characteristics of charged and discharged

CADNICA batteries after prolonged storage. Though

the capacity is recovered with a couple of

charge/discharge cycles in either case, the capacityrecovery of a discharged battery is more quickly

achieved.

Due to differences in self-discharge rate, sealed cells

in a CADNICA assembled battery may have varying

degrees of available capacity after having been in

storage for an extended period of time, so they should

be recharged prior to being returned to service. I f this

is not done, polarity reversal may occur in some of the

cells. I t is advisable for prolonged storage that

batteries be in the discharged state.

Fig.4-4:Fig.4-4:Fig.4-4:Fig.4-4: Charged StorageCharged StorageCharged StorageCharged Storage vsvsvsvs

Discharged StorageDischarged StorageDischarged StorageDischarged StorageN -1300 S C

50

60

70

80

90

100

1 2 3 4 5

S torage at discharge state

S torage at charge state

R eco very after 2ye ars.stored at 35


C ap acity m ea suring con ditions:C harge:0.1It16H rs.D isch arge :0.2It, E .V .=1.0VTe m p erature:20


18/52- 17 -

4-2-34-2-34-2-34-2-3 Storage periodStorage periodStorage periodStorage period Sanyo CADNICA batteries can be stored indefinitely

without the deterioration of electrodes, which is often

observed in lead-acid batteries.

Fig.4-5 illustrates sample cases concerning the cycle

characteristics of cells stored for 3, 5 and 10 years

respectively.

Even in the case of long-term storage, the cells high

rate capacity does not significantly decrease and

superior cycle characteristics are maintained.

Fig.4-5Fig.4-5Fig.4-5Fig.4-5 Cycle Characteristics AfterCycle Characteristics AfterCycle Characteristics AfterCycle Characteristics After

Prolonged StorageProlonged StorageProlonged StorageProlonged StorageN -600A A

0

60

20

80

40

1000 200 300 4 00 500

S torage for 3 years



C apacity m e asu ringcond ition s:C h arge:0.1It16H rs.D ischarge:0.2It,E .V .=1 .0V

Te m p.:20

C ycle cond ition s:C harge:0.1It11 H rs.D isch arge :0.7It1H r.Te m p.:20

100


S torage at 20 in discharged state

4-34-34-34-3 Items to beItems to beItems to beItems to be Remembered forRemembered forRemembered forRemembered for

StorageStorageStorageStorage

Though CADN ICA batteries are maintenance-free,and require no supply of electrolytes, or water during

storage, the following guidelines should be observed

to make best use of battery capacity:

(1) Batteries should be completely discharged prior

to prolonged storage.

(2) Batteries should be stored at the possible lowest

temperature. The temperature should never

exceed +35 for prolonged storage.

(3) Batteries should be recharged prior to use after

prolonged storage.


19/52

5 atteryService Life5-1 G eneral

5-2 Factors Influencing Service

Life

5-3 Sum m ary of Service Life

5 1 G eneral The service li fe is defined as, The length of time it

takes a battery to reach a state of wear-out failure,

where it can no longer drive the necessary load. Herethe wear-out failure denotes the failure during the

period when the failure rate increases with time due

to the elements of fatigue, abrasion of aging, and is

distinguished from the initial failure and the random

failure, which denote the failure due to errors in

design/production or unsuitable specifications, and

accidental failure, between the initial failure and the

wear-out failure period, respectively.

Fig.5 1: Failure Rate Curve

0

Initial failure period

R andom failure pe riodW ear-out failurepe riod

Service Life

FailureRate

The wear-out failure of CADNICA batteries is

classified into 2 types. One is due to an internal short

circuit caused by changes in active materials and the

deterioration of organic materials, such as a

separator. The other is due to the electrolyte drying

up. In normal charge and discharge cycles no

electrolyte will leak outside the cell due to CADNICA

batterys completely sealed structure. A small

amount of leakage may occur from the safety vent or

the sealed part if the battery is charged with a

current higher than specified, overdischarged until

polarity reversal occurs, or used at extremely

high/low temperatures. Repeated loss of electrolyte

will eventually increase internal resistance and

decrease capacity.

The service li fe of CADNICA batteries is generally

considered to terminate when their availablecapacity has been lowered to less than 60% of the

nominal capacity.

This rule, however, is not applicable in conditions

where, depending upon operating requirements, the

termination point of their service life is set higher or

lower than the above mentioned level. Shown in

Fig.5-2 is the number of charge/discharge cycles in

relation to discharge capacity. CADNICA batteries

exhibit excellent cycle characteristics where no

noticeable drop is observed after 500 charge/

discharge cycles under Sanyo specified conditions.

In addition, CADNICA batteries exhibit excellentcycle characteristics even for pulse discharge cycle

applications.


20/52

ing. As the figures demonstrate, CADNICA batteries

can be used for extremely long periods on continuous

charge cycles.

Fig.5 2: C ycle CharacteristicsN -1300SC

0

60

20

80

40

2000 400 600 800 1000

C apacity m easuring conditions:C harge:0.1It16H rs.D ischarge:0.2It,E .V.1.0VTe m perature:20

C ycle condition s:C harge:0.1It11H rs.D ischarge:0.7It1H rs.Te m perature:20

100

Number of Cycles

Fig.5 3: Pulse Discharge C ycleCharacteristics

N -1300SC

0

60

20

80

40

1000 200 300 400 500

C ap acity m easuring cond itions:C harge:0.1It16H rs.D ischarge:0.2 It,E .V.1.0VTem p:20

C ycle condition s:C harge:0.1It16H rs.D ischarge:resistan ce(10It30sec 1It30sec.)20M ins.Tem p:20

100

Number of Cycles

Fig.5 4: C ontinuous Trickle ChargeCycle C haracteristics

KR-SCH(1.2)

0

60

20

80

40

10 2 3 4 5

C harge:It/30~6MonthsDischarge:1It,E.V.1.1VTemp:20

100

Service Life (Years)

5 2 Factors Influencing ServiceLife

5 2 1 C ell Tem perature One of the most important factors affecting the

service life of a CADNICA battery is ambient

temperature. F ig.5-5 illustrates an approximate

relation between ambient temperature and battery

service life. Generally speaking the optimum

temperature is room temperature and temperatures

higher than 40 will deteriorate cell performance.

Exposure to a high temperature for a short time

however will not cause permanent damage and will

recover with a couple of charge/discharge cycles at

room temperature. The most adverse effects of a

prolonged rise in cell temperature may be seen as

damage to organic materials. Used at hightemperatures for a long time, the separator in

particular is gradually damaged, and its insulation

function decreases, resulting in internal short circuit.

Overcharging and continuous charging at high

temperatures should be avoided. This accelerates

deterioration of the separator through oxidization

resulting from oxygen generated at the positive

electrode during overcharging.

Fig.5 5: Am bient Tem perature andBattery Service Life

5

10

20

30

40

60

80

100

0 10 20 30 40 50 60

5 2 2 C harge C onditions The charge current of a CADNICA battery is

specified according to its design. As long as a

CADNICA battery is charged at an input rate below

the specified value, internal gas pressure remains at

a low level. However, heat generated by gas

recombination causes a rise in cell temperature.

When overcharging is repeated often, heat deter-

iorates the cell and shortens its service life. Charging

at rates over specified value increases internal gas

pressure, occasionally causing operation of the gas

release vent and should be avoided.

The batteries as standby power sources of

emergency lights or signal lights, are continuouslycharged with trickle charge current in order to

maintain a fully charged state Nickel-Cadmium


21/52

observed in CADNI CA batteries.

5 2 3 Discharge C onditions Even when fully discharged, a CADNICA battery

recovers its capacity by charging. Over-discharge hasonly a minor effect on CADNICA batteries compared

with lead-acid batteries.Depth of dischargeis the

term used to express percentage wise the capacity

removed from a battery at the onset of discharge from

the state of full charge. The number of cycles

CADNICA batteries can withstand depends on the

depth of discharge as illustrated in Fig.5-6. When the

cell is discharged to a greater depth, the number of

cycles decreases.

Fig.5 6: Discharge Depth and BatteryService Life10000

5000

3000

2000

1000

700

500

300

20010 20 30 40 50 60 70 80 90 1 000

C harge curren t:0.1It

C harge input:150% of

discha rge d capacity

D ischarged :1It

Te m perature:20

NumberofCycles

Nickel-Cadmium batteries have a memory-effect

in which the voltage drops by 2 levels during

discharge after shallow charge/discharge cycles. In

application when discharge end voltage is highly

established, apparent decreases in capacity and

operating voltage are shown. This phenomenon

doesnt occur after 1 or 2 complete discharge cycles.

Fig.5 7: M em ory EffectKR- 1100AEL

0 10 20 30 40 50 60 70

0.8

1.0

1.2

1.4 Initial

1st after 100 cycles

2nd after 100 cycles

3rd after 100 cycles

C ycle condition s:

C harge:0.1It10H rs.

D ischa rge:1It10M ins.

Te m perature:45

D isch arge C ha racteristics Testing C on dition s:


D isch arge:1It

Te m perature:20

The battery performance is hardly affected by the

discharge frequency during continuous charge of

reserve power supply, as il lustrated in F ig.5-8, which

represents the continuous charge cycle characte-ristics in 3, 6 and 12 months.

Fig.5 8: Discharge Frequency andC ycle Characteristics

KR-SCH(1.2)

20

40

60

80

120

0.50 1 1.5 2 2.5 3

3 m onth cycle

6 m onth cycle

1 year cycle

C harge It/303,6,12M onthsD ischarge:1It,E .V .1.1VTem perature:20

100

5 3 Sum m ary of Service Life In the preceding paragraphs various factorsaffecting the service life of Sanyo CADNICA batteries

have been discussed. The conclusion of the discussion

is that, if they are used under normal operating

conditions, a very long service life can be expected.

CADNICA battery life is determined by these factors

which relate to one another in an intricate manner.

Thus, it is difficult to predict how long they will

generally perform well.

The relevant factors to battery life are summarized

below:

Batterycyclelife

Degradation inelectrode performance

Variation inelectrolytedistribution

Deterioration ofconstituents

Crystal growth inactive materials

Loss of electrolyte Venting

Reverse charge

Charging at ahigher rate thanspecified.

Overcharge

Intermittent charge

High ambienttemperature

Overcharge

Rise in internaltemperature(high-ratecharge/discharge)

High ambient

temperature

Extremely low currentdischarge

Good understanding of these relevant factors will

assist the designer of battery-powered devices in

obtaining the longest life, optimum performance, and

greatest reliability from Sanyo CADNICA batteries.


22/52- 21 -

6SpecialSpecialSpecialSpecial

PurposePurposePurposePurpose

BatteriesBatteriesBatteriesBatteries6-1 High-Capacity CADNICA

Batteries

6-2 Fast-Charge CADNICA

Batteries

6-3 High-Temperature

CADNICA Batteries

6-4 Heat-Resistant CADNICA

Batteries

6-5 Memory-Backup

CADNICA Batteries

(CADNICA BACKUP)

CADNICA Batteries may be used in various fields

with excellent results as mentioned before. Sanyo has

designed CADNICA batteries for special purposes

that concur with necessary requirements, and

further improve the efficiency of the devices in which

they are used.

The basic structural design of CADNICA batteries

for exclusive use, is the same as that of standard

CADNICA batteries. The characteristics of

CADNICA batteries for exclusive use succeedrespective excellence of standard CADNICA batteries.

CADNICA batteries for exclusive use are by no

means limited to a particular field, but may be used

for many purposes.

6-16-16-16-1 High-Capacity CADNICAHigh-Capacity CADNICAHigh-Capacity CADNICAHigh-Capacity CADNICA

BatteriesBatteriesBatteriesBatteries

6-1-16-1-16-1-16-1-1 CharacteristicsCharacteristicsCharacteristicsCharacteristics The growing use of compact and l ightweight

equipment has rapidly increased the need for a high-capacity battery. In anticipation of this trend, Sanyo

has developed high-capacity CADNICA batteries

with approx. a 40-percent higher capacity featuring a

significant improvement in energy density while

employing the same manufacturing method used for

highly-reliable standard CADNICA batteries. They

can also be charged in as little as one hour.

6-1-26-1-26-1-26-1-2 Charge CharacteristicsCharge CharacteristicsCharge CharacteristicsCharge Characteristics High-capacity CADNICA batteries are designed forimproved gas recombination in order to facilitate fast

charging. They are capable of one-hour charging viaV sensor fast charge system.

Fig.6-1 shows the charge characteristics forV

sensor fast charging.

Please refer to Chapter 7-3 for information

regarding V sensor fast charging.

Fig.6-1:Fig.6-1:Fig.6-1:Fig.6-1: Charging CharacteristicsCharging CharacteristicsCharging CharacteristicsCharging Characteristics

0

0.5

1.0

1.5

0

50

40

30

20

10

10 20 30 40 500

KR -1800SC E

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

C ell tem perature

Internal gus p ressure

C ha rge:1.5It(V=10m V/cell)Temperature:20

C ell voltag e


23/52- 22 -

6-1-36-1-36-1-36-1-3 DischargDischargDischargDischarge Characteristicse Characteristicse Characteristicse Characteristics The discharge voltages of standard CADNICA batt-

eries show extremely smooth voltage characteristics

up to the end of the discharge period. High-capacity

CADNICA batteries share this advantage, and in

addition, through a significant improvement in

energy density, they exhibit a capacity 40% greater

than previous models.

Fig.6-2 shows the discharge characteristics of high-

capacity CADNICA batteries, while Fig.6-3 shows therelationship between discharge current and discha-

rge capacity. As the figures demonstrate, high-

capacity CADNICA batteries maintain a higher

capacity than standard CADNICA batteries at low,

medium or high current discharge levels.


0.4

1.0

1.2

1.6

100 20 3 0 40 5 0 6 0 70

C ha rge:0.1 It16Hrs.Discharge:1.7ATemperature:20

Standa rdC adnicaba tteries(N -130 0S C )

H igh -capacityC adn icaba tteries(KR -1800S C E )

0.6

0.8

1.4

Fig.6-3:Fig.6-3:Fig.6-3:Fig.6-3: Discharge Current andDischarge Current andDischarge Current andDischarge Current and

Discharge CapacityDischarge CapacityDischarge CapacityDischarge Capacity

1.0

0.8

0.6

1.4

1.2

2.0

1.8

1.6

42 6 8 10 12 140

S tanda rdC adnica batteries(N -1300SC )

H igh -cap acityC ad nica b atteries(KR -1800SC E)


D ischarge:E.V .1.0V

Te m perature:20

6-1-46-1-46-1-46-1-4 Service LifeService LifeService LifeService Life The service li fe of high-capacity CADNICA batteries

differs according to the conditions of use. The

manufacturing process for high-capacity CADNICA

follows that of standard CADNICA batteries, which

have consistently demonstrated high reliability.

Therefore high-capacity CADNICA batteries also

attain a cycle service life equivalent to that of

standard CADNICA batteries.

Fig.6-4 shows an example of cycle characteristics

with V sensor fast charging. It is possible to use

high-capacity CADNICA batteries for more than 500

charge/discharge cycles.

Fig.6-4:Fig.6-4:Fig.6-4:Fig.6-4: Cycle CharacteristicsCycle CharacteristicsCycle CharacteristicsCycle CharacteristicsKR -1800SC E

0

60

20

80

40

1000 200 300 400 500

Number of Cycles

C ycle con ditions:C harge:1.5 It( 10m V /cell)D ischarge:1It55M ins.Tem perature:20

100

C apa city m easu ringcond ition s:C harge:1.5It( V10m V /cell)D ischarge:1It,E .V .1.0V

Tem perature:20

6-26-26-26-2 Fast-Charge CADNICAFast-Charge CADNICAFast-Charge CADNICAFast-Charge CADNICA

BatteriesBatteriesBatteriesBatteries

6-2-16-2-16-2-16-2-1 CharacteristicsCharacteristicsCharacteristicsCharacteristics Standard CADNICA batteries require a charging

period of 14 to 16 hours at a standard charge current

of0.1It. I n order to meet demands for a faster

charging speed, fast-charge CADNICA batteries havebeen developed. Designed to facilitate recombination

of oxygen gas generated at the electrode, they offer

the following advantages:

(1) One-hour quick-charge capability

With the temperature sensor fast-charge system or

the V sensor fast charge system, charging time

can be reduced to as little as approx. one hour.

ForV sensor fast charging and temperature

sensor fast charging, see chapter 7-3.

(2) Excellent high current discharge characteristics

Through the use of Sanyos original highly-efficient

current collecting method, plus an electrode that

demonstrates superior discharge characteristics,these batteries possess excellent voltage characteri-

stics at high rate discharge.


24/52- 23 -

6-2-26-2-26-2-26-2-2 Operating Principle of Fast-Operating Principle of Fast-Operating Principle of Fast-Operating Principle of Fast-

Charge CADNICA BatteriesCharge CADNICA BatteriesCharge CADNICA BatteriesCharge CADNICA Batteries Sanyo CADNICA batteries generate oxygen at the

positive electrode as the state of full charge is

approached, according to the following equation, as

discussed already in 1-4.

4OH 2H2O+O2+4e (1)

In the overcharge region, the charging current is

completely consumed in gas generation. When the

charge current isaA, oxygen gas is generated at a

rate of 208 a ml/hr. at 1atm and 20. Generated

gas is recombined at the negative electrode according

to the following formulas:

Cd+1/2O2+H2O Cd(OH)2 (2)

O2+2H2O+4e 4OH (3)

Oxygen gas is generated in proportion to the charge

current so that the oxygen consumption reaction in

Eqs. (2) and (3)must be accelerated in order to charge

at a higher current. Otherwise, unconsumed oxygen

gas increases the internal pressure to such a level

that the safety vent will operate. As seen from Eqs.

(2) and (3), the oxygen consumption reaction takes

place in the 3-phase zone where the 3 phases,

electrolyte (liquid), oxygen(gas)and electrode(solid),

come into contact with each other.

Fast-charge CADNICA batteries are specifically

designed in terms of electrode structure and

electrolyte distribution so that a large number of 3-

phase zones may be formed. This design makes

possible fast charging over a period of approx. 1 hour.

With the temperature-sensor fast-charge system,the charging condition is assessed by detecting the

surface temperature of the battery. The oxygen gas

recombination reaction at the negative electrode is

shown by the above Eqs.(2) and (3). Eq. (2) details an

oxidized reaction of the metal cadmium, which

results in high heat generation. This heat in turn

causes an increase in the battery surface

temperature. Fast-charge CADNICA batteries are

designed for faster recombination of generated

oxygen gas and feature improved internal heat

conductivity, making a quick increase in surface

temperature possible.

6-2-36-2-36-2-36-2-3 Charge ChaCharge ChaCharge ChaCharge Characteristicsracteristicsracteristicsracteristics Fig.6-5 shows the charge characteristics of fast-

charge CADNICA batteries in comparison with

standard CADNICA batteries. In order to increase

gas recombination capability, fast-charge CADNICA

batteries possess a slightly reduced cell capacity.

Therefore their peak voltages appear earlier during

the charging cycle.

Fast-charge CADNICA batteries show lower charge

voltages at the end of charging due to the ease with

which heat is generated within the cell, a result of

their high capability for oxygen gas recombination.

Fig.6-5:Fig.6-5:Fig.6-5:Fig.6-5: Fast-Charge CharacteristicsFast- Charge CharacteristicsFast- Charge CharacteristicsFast- Charge Characteristics

0

10

20

30

40

50

60

70

C ell voltag eC harge:1.5It

C ut-off tem perature

N-1300SCR

N -1300SC

Internal gus pressure

1.0

1.1

1.2

1.3

1.4

1.5

1.6

0

0.5

1.0

1.5

20 30 40 50 60100

C ell tem perature

The internal gas pressure of a standard CADNICA

battery cell quickly increases during charging, while

that of a fast-charge CADN ICA battery stabil izes at

approx. 5kg/cm2.

When only gas recombination is taken into

consideration, fast-charge CADNICA batteries can be

said to be capable of withstanding overcharging at a

current level as high as 1.5It. I f overcharging

continues, however, the cell temperature will

continue to increase. After a time, it may badly

damage the battery. I n order to prevent the

occurrence of this problem, fast charging must be

suspended after the appropriate amount of time.

Fig.6-6 shows the relationship between the level of

overcharge current and the internal gas pressure,

while Fig.6-7 shows the relationship between the

ambient temperature during charging and the

internal gas pressure.


25/52- 24 -

Fig.6-6:Fig.6-6:Fig.6-6:Fig.6-6: Overcharge Current andOvercharge Current andOvercharge Current andOvercharge Current and


1 2 3 4

1.0

1.2

1.4

1.6

1.8

2.0 N -1300 S C R

0.8

0.6

0.4

0.2

00

Te m perature:20

Fig.6-7:Fig.6-7:Fig.6-7:Fig.6-7: Ambient Temperature andAmbient Temperature andAmbient Temperature andAmbient Temperature and


10 20 30 40

1.0

1.2

1.4

1.6

1.8

2.0N-1300SCR

0.6

0.4

0.2

C harge:1.5 It

00

0.8

6-2-46-2-46-2-46-2-4 DischargeDischargeDischargeDischarge CharacteristicsCharacteristicsCharacteristicsCharacteristics Fast-charge CADNICA batteries employ sintered

plates which exhibit excellent discharge character-

istics for both the positive and negative electrodes. In

addition, through the utilization of Sanyos original

highly-efficient current collecting method which

demonstrates superior discharge characteristics,these batteries offer an extremely stable discharge

performance, even at high current levels.

Fig.6-8 shows an example of discharge characteris-

tics.


0 20 40 60 80 100 120

N -1300 S C R

1.2

1.0

0.8

1.4

0.2It1It4 It8 It

C ha rge:1.5 It to 45Tem perature:20

6-2-56-2-56-2-56-2-5 Temperature CharacteristicsTemperature CharacteristicsTemperature CharacteristicsTemperature Characteristics

One of the greatest features that V-sensor and

temperature-sensor fast-charge systems offer is the

capability of achieving stable cell capacity over a

wide range of temperatures. However, at low temp-

erature, gas recombination capacity is reduced and

internal gas pressure can increase to a level that

adversely affects service life. Therefore, be sure to

perform fast-charging under the specified tempera-ture. Fig.6-9 shows charge temperature character-

istics.

Fig.6-9:Fig.6-9:Fig.6-9:Fig.6-9: Charge TemperatureCharge TemperatureCharge TemperatureCharge Temperature


10 20 30 40 50

80

90

100

110 N -1300 S C R

60

500

70

C harge:1.5 It to 45D ischa rge:1It,E .V .1.0V

6-2-66-2-66-2-66-2-6 Service LifeService LifeService LifeService Life The gas recombination capability does not decline

even after many cycles. Battery service life does,

however, differ according to ambient conditions.

Although the factors affecting the service life of

fast-charge CADNICA batteries are essentially the

same as those of standard CADNICA batteries, the

charging conditions of the two are very different. In

the case of fast-charge models, the period of

overcharge from the onset of temperature increase to

charge cut-off, should be made as short as possible in

order to ensure a long service life. Therefore the

following precautions should be observed when

designing fast-charge control circuits.

(1) Temperature-sensor fast-charge control

(a) In the case of assembled batteries that easily

radiate heat it takes a long time to reach the

cut-off temperature. Sanyo recommends a

design under which temperature increases are

maximized, either by thickening the materialsof the battery case or by utilizing materials

which feature low heat conductivity.

(b) Charged with a temperature-sensor system,

CADNICA batteries tend to be overcharged in

proportion to the difference between the

ambient and cut-off temperatures. Decrease

the setting value of the cut-off temperature

when using at low temperature.

(2) V-sensor fast-charge control

(a) In the case of assembled batteries that easily

radiate heat, cell voltage decreases gently after

reaching its peak. Sanyo recommends a design


26/52- 25 -

under which temperature increases are

maxim-ized, especially for CADNICA batteries

of small capacity.

(b) The higher theV value becomes, the more

the battery becomes overcharged. Set theV

value to 10~20mV per single cell.

Fig.6-10 shows temperature-sensor fast-charge cycle

characteristics. Use for more than 500 charge/disch-

arge cycles is possible.

Fig.6-11 shows continuous-charge cycle characteris-tics.

F ig.6-12 shows super-fast-charge cycle characteris-

tics. Use for more than 500 charge/discharge cycles is

possible.

Fig.6-10:Fig.6-10:Fig.6-10:Fig.6-10: Cycle CharacteristicsCycle CharacteristicsCycle CharacteristicsCycle CharacteristicsN -1300SC R

0

60

20

80

40

1000 200 300 400 500

Number of Cycles

C ycle conditions:C harge:1.5It to 45D ischarge:1It55M ins.T em perature:20

100

C apacity m easurem ent:C harge:1.5It to 45D ischarge:1It,E .V .1.0VTe m perature:20

Fig.6-11:Fig.6-11:Fig.6-11:Fig.6-11: Continuous-ChContinuous-ChContinuous-ChContinuous-Charge Cyclearge Cyclearge Cyclearge Cycle

CharacteristicsCharacteristicsCharacteristicsCharacteristicsN -1300 S C R

Number of Cycles

0

60

20

80

40

100 20 30 40 50

100

C apacity m easurem ent:C harge:0.3It5H rs.D isch arge :1It,E .V .1.0VTe m perature:20

C ycle con dition s:C harge:0.3 It1W eekD isch arge :1It,E .V .1.0VTe m p erature:20

Fig.6-12:Fig.6-12:Fig.6-12:Fig.6-12: Super-Fast- Charge CycleSuper-Fast-Charge CycleSuper-Fast-Charge CycleSuper-Fast-Charge Cycle

CharacteristicsCharacteristicsCharacteristicsCharacteristicsN -1300 S C R

Number of Cycles

0

60

20

80

40

1000 200 300 400 500

C apacity m easurem ent:C harge:4It15M ins.D isch arge :1It,E .V .1.0VTe m p erature:20

C ycle con dition s:C harge:4It15 M ins.D isch arge :1It,E .V .1.0VTe m p erature:20

100

6-36-36-36-3 High TemperatureHigh TemperatureHigh TemperatureHigh Temperature

CADNICA BatteriesCADNICA BatteriesCADNICA BatteriesCADNICA Batteries

6-3-16-3-16-3-16-3-1 Advantages of High TemperatureAdvantages of High TemperatureAdvantages of High TemperatureAdvantages of High Temperature

CADNICA BatteriesCADNICA BatteriesCADNICA BatteriesCADNICA Batteries Being maintenance-free, and having a high all-

owance for overcharge, which no other secondary

batteries have, high temperature CADNICA batteriesare highly suitable for use in emergency lighting. For

use in this case, the batteries are continuously

charged with a low current, (trickle-charged), at a

relatively high temperature, (35 to 45). High

temperature CADNICA batteries were designed to

meet necessary requirements for use in high

temperature situations. Advantages in using high

temperature CADNICA batteries are:

(1) Outstanding charge/discharge characteristics at

high temperature.

The high temperature CADNICA battery has a

high trickle-charge efficiency even in tempera-

ture as high as 35 to 45.(2) Long service life and high reliability.

The high temperature CADNICA battery shows

a minor cycle-deterioration even at high

temperature, and also withstand overcharge,

ensuring a long service life.

6-3-26-3-26-3-26-3-2 Operating Principles of HighOperating Principles of HighOperating Principles of HighOperating Principles of High

Temperature CADNICATemperature CADNICATemperature CADNICATemperature CADNICA

BatteriesBatteriesBatteriesBatteries The charging of Nickel-Cadmium batteries in

general becomes more difficult at higher temperature,

and with lower current. As explained in Chapter 2,

this is because the charging reaction of active

material (1), and the oxygen generation reaction (2),

compete with each other at the positive electrode

towards the end of charging.

Ni(OH)2+ OH NiOOH + H2O+e

(1)

4OH 2H2O+O2+4e (2)

When oxygen gas is generated, the charging

reaction at the positive electrode becomes reluctant

to proceed. The generation potential of oxygen

becomes lower with the increase of cell temperature,so that oxygen is generated in the earlier stage. As a

result, the charge voltage is low, the charge efficiency

at the electrode deteriorates, and the charge capacity

becomes lower.

The high temperature CADNICA battery is made

with specially designed electrodes and electrolyte, in

order to maintain a high generation potential of

oxygen, even at high temperature.


27/52- 26 -

6-3-36-3-36-3-36-3-3 Temperature CharacteristicsTemperature CharacteristicsTemperature CharacteristicsTemperature Characteristics The high temperature CADNICA battery guaran-

tees its outstanding characteristics even in high

temperature. Fig.6-13 il lustrates cell capacity as a

function of ambient temperature where the cell

capacity at 20 is taken as a standard (100%). The

high temperature CADNICA battery exhibits maxi-

mum capacity at just over 20. Though its high

temperature characteristics are much improved as

compared with those of the standard CADNICAbattery, the high temperature CADNICA battery has

slightly lower discharge capacity at low temperature,

as a result of improving its high temperature quality.

However, the high temperature CADNICA battery

can withstand a charge at 0, and a discharge at

20, as well as the standard CADNICA battery, so

no practical problem exists.

Fig.6-13:Fig.6-13:Fig.6-13:Fig.6-13: Temperature CharacteristicsTemperature CharacteristicsTemperature CharacteristicsTemperature Characteristics

50

80

90

110

100 20 3 0 40 5 0 60 70

C harge :It/3048H rs.D isch arge :1It,20,E.V.1.1V

S tandard C A D N IC A

H igh tem perature

C A D N IC A

60

70

100

6-3-46-3-46-3-46-3-4 Charge CharacteristicsCharge CharacteristicsCharge CharacteristicsCharge CharacteristicsThe high temperature CADNICA battery is usually

used at a trickle-charge of It/20 to It/50. Fig.6-14

illustrates the trickle-charge voltage characteristicswith I t/30 current. The charge voltage of the high

temperature CADNICA battery is slightly higher

than that of the standard CADNICA battery due to

the improvement of its oxygen generating potential,

as mentioned in 6-3-2.

Fig.6-14:Fig.6-14:Fig.6-14:Fig.6-14: Trickle-Charge VoltageTrickle-Charge VoltageTrickle-Charge VoltageTrickle-Charge Voltage


0 2 0 40 60 8 0 1 00 12 0 1 40 16 0 1 80 20 0

KR -SC H(1.2)

1.1

1.5

1.6

1.7

1.2

1.3

1.4

0

20

40

60

C ha rge:It/30

6-3-5 Discharge Characteristics6-3-5 Discharge Characteristics6-3-5 Discharge Characteristics6-3-5 Discharge Characteristics The high temperature CADNICA battery has the

same basic structure as the standard CADNICA

battery. Thus, its discharge voltage exhibits a flat

characteristics at the same voltage level as the

standard CADNICA battery. The high temperature

CADNICA battery shows improved discharge charac-

teristics when trickle-charged in high ambient

temperature. Figs.6-15 and 6-16 illustrate the high

temperature trickle-charge characteristics, examples

A and B, 45 characteristics as specified by J IS

C 8705, respectively.

The discharge voltage drop often observed in

Nickel-Cadmium batteries is only slightly detect-ablein CADNICA batteries when charged continuously at

high temperatures.

Fig.6-15:Fig.6-15:Fig.6-15:Fig.6-15: High Temperature Trickle-High Temperature Trickle-High Temperature Trickle-High Temperature Trickle-

Charge CharacteristicsCharge CharacteristicsCharge CharacteristicsCharge Characteristics

Example AExample AExample AExample A

Discharge Time( Mins.)

1.0

0.8

1.2

1.4

10 20 30 40 50 600

S tanda rdCAD NICA

H ightem peratureCAD NICA

C harge:It/3048H rs.D ischarge:1ItTem p:45

Fig.6-16:Fig.6-16:Fig.6-16:Fig.6-16: High Temperature Trickle-High Temperature Trickle-High Temperature Trickle-High Temperature Trickle-

Charge CharacteristicsCharge CharacteristicsCharge CharacteristicsCharge Characteristics

Example BExample BExample BExample B

1.0

0.8

1.2

1.4

10 20 30 400

S tanda rdCAD NICA

H igh tem peratureCAD NICA

C harge:It/3024H rs.D ischarge:1ItTem p:45


28/52- 27 -

6-3-66-3-66-3-66-3-6 Service LifeService LifeService LifeService Life The service life of the high temperature CADN ICA

battery depends largely on the ambient conditions, as

mentioned in Chapter 5, though expected as over 4

years under normal conditions. F ig.6-17 il lustrates

cycle characteristics

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